Detergents in gel form can present many advantages, for example, ease of use and concentrated cleaning ability. Dishcare gels are preferred for use in washing dishes in some parts of the world. The gel product form best lends itself to the "direct application" habit in which persons apply a wet sponge or other cleaning applicator directly onto the dishcare detergent and then onto the dishes; the dishes are then typically washed and rinsed under running water. Additionally, dishcare gels can be stored in inexpensive tubs or similar packages instead of the more complex plastic bottles required for dishwashing liquids.
It is important for detergent gels to have excellent sudsing properties, and to provide good cleaning and other performance benefits. It is also desirable for detergent gels to have an attractive appearance and to be easy to process. Moreover, it is desirable to make such detergent gels from ingredients that are relatively inexpensive so that the detergent gels are affordable to consumers.
U.S. Pat. No. 4,615,819 issued to Leng, Machin, Reed and Erkey on Oct. 7, 1986 discloses detergent gel compositions in hexagonal liquid crystal form. This patent requires, as an essential component of its gels, an additive which is a water-soluble non-micelle-forming or weakly micelle-forming material capable of forcing the surfactant system of the product into hexagonal phase. The patent states that without this additive the transition into the hexagonal phase will not take place. The additives disclosed in this patent, as being capable of forcing such hexagonal phase, are materials useful as hydrotropes in light-duty liquid detergent compositions. These additives contain a large polar group and, optionally, a small hydrophobic group, such as an aliphatic or araliphatic chain containing not more than 6, preferably 4 or less, aliphatic carbon atoms. The larger the polar head group, the larger hydrophobe that can be tolerated. The polar group of the additive may carry an ionic charge, but if so it must be of the same polarity as that of the surfactants in the product. Such hydrotropes disclosed in the patent include short-chain analogs of surfactants, such as lower aryl or alkylaryl sulfonates, i.e., toluene and xylene sulphonates. Preferred hydrotrope additives disclosed have the same or a similar polar group as the surfactant used in the gel, but with a relatively short hydrocarbon chain containing at most 6, and preferably not more than 4, aliphatic carbon atoms. Other preferred hydrotrope additives disclosed include short chain ammonium salts, such as triethanolamine hydrochloride or lower alkylbenzene dimethyl ammonium hydrochlorides when the surfactant of the product is cationic. Also preferred hydrotrope additives disclosed are highly polar but uncharged materials which may be used in conjunction with both anionic and cationic surfactants in the product. Short chain analogues of nonionic surfactants are also disclosed as such additives. Other preferred uncharged hydrotrope additives disclosed are lower amides, especially urea. Short-chain urea homologues and analogues, for example, methyl and ethyl ureas, thiourea, formamide and acetamide, are other hydrotrope additives disclosed.
It is an object of the present invention to provide detergent compositions in the form of gels.
It is a particular object of the present invention to make detergent gels that have excellent sudsing characteristics, including a large amount of rich, long-lasting suds.
It is also an object of the present invention to make detergent gels that provide good cleaning and other performance benefits in addition to the excellent sudsing.
It is another object of the present invention to provide detergent gels that have an attractive appearance and that are easy to process.
It is a further object of the present invention to make such gels from relatively inexpensive ingredients so that the gels are affordable to consumers.
These and other objects of the invention will be described in further detail herein.